tag:blogger.com,1999:blog-3891434218564545511.post538459233188231835..comments2024-03-27T20:37:09.185-05:00Comments on Alexander Pruss's Blog: Energy conservationAlexander R Prusshttp://www.blogger.com/profile/05989277655934827117noreply@blogger.comBlogger9125tag:blogger.com,1999:blog-3891434218564545511.post-73127177070191009672019-08-04T13:42:37.804-05:002019-08-04T13:42:37.804-05:00Noether's theorem requires two things:
1. min...Noether's theorem requires two things:<br /> 1. minimization of action<br /> 2. symmetries.<br />Both are puzzling on the Humean and Aristotelian pictures, indeed I think just as puzzling as the conservation laws. (Leibniz talked of how special cases of 1 provided an argument for the existence of God.)Alexander R Prusshttps://www.blogger.com/profile/05989277655934827117noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-50152472389046540922019-08-02T19:54:06.559-05:002019-08-02T19:54:06.559-05:00Noether's theorem (or a generalization of) acc...Noether's theorem (or a generalization of) accounts for the big-name conservation laws, even down to QFT. Really anything that can be stated in a Lagrangian (or Hamiltonian) formulation.<br /><br />I think this does really affect the interpretative work we have to do. For example, the Lagrangian minimizes the Action, and this is given as brute instead of the conservation laws themselves. I think a minimalization-of-action metaphysics of a (largely) symmetrical universe doesn't really seem prima facie bad, and certainly better than "there's just conservation laws". It is as above not inherently teleological since you can just define it to optimize over possible worldpaths, but it fits nicely into a teleological definition as well.Anonymoushttps://www.blogger.com/profile/08683467720543198558noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-66437527580239725332019-07-24T11:08:34.663-05:002019-07-24T11:08:34.663-05:00Alex
Actually, I think it is mistaken not to thin...Alex<br /><br />Actually, I think it is mistaken <i>not</i> to think of causation as a transfer of some entity. I mean, if an entity X causes another entity Y to do something, 'something' (whatever that something may be) must go from X to Y. If that isn't the case, saying that X causes something in Y doesn't seem to mean anything at all.<br /><br /><br />Walter Van den Ackerhttps://www.blogger.com/profile/16101735542155226072noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-74674343728456168722019-07-24T09:23:38.932-05:002019-07-24T09:23:38.932-05:00Walter:
Leibniz thought that, too, which is why h...Walter:<br /><br />Leibniz thought that, too, which is why he concluded that there was no real causation between distinct substances (unless the cause was God; I am not sure why he thought himself entitled to that exception). But it seems mistaken to think of causation as a transfer of some entity.Alexander R Prusshttps://www.blogger.com/profile/05989277655934827117noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-61209601818774107012019-07-20T05:05:46.187-05:002019-07-20T05:05:46.187-05:00Alex
If energy isn't a "thing" that...Alex<br /><br />If energy isn't a "thing" that moves from one subtsnce to another, in what way can substance A be said to "cause" substance B to gain an accident? It seems to me there must be something from A that somehow "goes" to B. Walter Van den Ackerhttps://www.blogger.com/profile/16101735542155226072noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-2845316263607621472019-07-19T21:02:16.978-05:002019-07-19T21:02:16.978-05:00Even if we necessitate giving something up, why sh...Even if we necessitate giving something up, why should it be *energy*?<br /><br />(Maybe another thing to investigate is explaining why the dynamics is Hamiltonian. For given that, Noether's theorem will yield conservation of energy from temporal isotropy.)Alexander R Prusshttps://www.blogger.com/profile/05989277655934827117noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-79568053337339175702019-07-19T20:41:01.139-05:002019-07-19T20:41:01.139-05:00I think on pretty much any view, immaterial beings...I think on pretty much any view, immaterial beings acting in the material world violates the conservation of energy. But, in any case, I see now what you mean about the Aristotelian view.... Hm. Could we define the powers in terms that necessitate giving something up?Michael Gonzalezhttps://www.blogger.com/profile/05279261871735286117noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-24040775967869994902019-07-19T20:03:14.020-05:002019-07-19T20:03:14.020-05:00On an Aristotelian metaphysics, energy isn't a...On an Aristotelian metaphysics, energy isn't a thing that moves from one substance or another. It's just a way of describing the accidents of the substance. There is no compelling metaphysical reason why when substance A causes substance B to gain an accident of heat, substance A should lose an accident of heat at the same time. For on orthodox Aristotelianism, the accident isn't moving from one substance to another: A loses one accident and B gains another accident. <br /><br />I see no metaphysical reason why an object couldn't have the causal power to increase the heat of things around it without itself becoming colder. Many Aristotelians are Thomists, and Thomists believe in immaterial angels. An immaterial angel could speak to a group of people. In doing so, it would be making the air vibrate and hence heat up. But the angel wouldn't be losing energy, because immaterial things don't have any energy.Alexander R Prusshttps://www.blogger.com/profile/05989277655934827117noreply@blogger.comtag:blogger.com,1999:blog-3891434218564545511.post-14231899177854217422019-07-19T14:08:17.281-05:002019-07-19T14:08:17.281-05:00I don't see the problem in the deterministic s...I don't see the problem in the deterministic sort of chain reaction cases (viz., if something is acted on, and the energy produces action on its part, and it thus acts on something else, etc). I can't see where any "new" energy would come from, or why the energy transferred from one step in the chain to another shouldn't just be regarded as (at least, in some important senses) the very same energy that has continually been handed off at each link in the chain.<br /><br />When it comes to first order, active causation (such as that of a self-mover, like an animal or a person), there is a sort of leap; but, of course, Aristotle himself gives the step between the two levels, namely the "nutritive soul" or the level of explanations characteristic of a living creature. But, still, we do regard the energy we expend in our actions as having been borrowed from the creatures we ate, who in turn borrowed it from the Sun, etc....Michael Gonzalezhttps://www.blogger.com/profile/05279261871735286117noreply@blogger.com